The invention relates to a galley cooling system suitable for use in an aircraft to cool trolleys containing, for example, food to be supplied to the aircraft passengers and to a method of operating a galley cooling system of this kind.
At present, in modern passenger aircraft, meals and beverages to be supplied to the aircraft passengers during flight are stored in trolleys in the region of galleys until they are delivered to the aircraft passengers by the cabin crew. It is known, for example, from DE 41 05 034 A1, to cool trolleys placed in the region of the galleys of the aircraft and used to store food to be kept cool with the aid of autonomous cooling devices which work with cold air as the cooling medium and are each equipped with their own compression refrigerating machine (air chiller). Alternatively to this, DE 43 40 317 C2, DE 10 2006 005 035 B3, WO 2007/080012 A1, DE 10 2009 011 797 A1 and US 2010/0251797 A1, for example, describe central cooling systems with a central compression refrigerating machine whose refrigerating capacity is distributed via a cooling circuit to a plurality of cooling stations arranged in the region of the aircraft galleys. The cooling stations supplied with cooling energy by the central refrigerating machine release this cooling energy to trolleys placed in the region of the galleys of the aircraft and used to store food which is to be kept cool, via cooling air circuits which are thermally coupled to the cooling circuit via corresponding heat exchangers.
Irrespective of whether the cooling energy required for cooling the food to be kept cool is provided by an autonomously working air chiller or a central cooling system of the aircraft, two different systems for supplying cooling air to the food to be cooled may be used, which are described, for example, in DE 10 2010 031 909 A1 and WO 2012/025200 A1. So-called air-over systems comprise a heat-insulated cooling chamber sealed against leakages, through which flows cooling air provided by the air chiller or the central cooling system. The trolleys loaded with the food to be cooled can be pushed into the cooling chamber. Trolleys suitable for use in an air-over system are not insulated themselves, but rather have air openings which allow unhindered circulation of cooling air from the cooling chamber through the trolleys and consequently over the food held in the trolleys which is to be cooled. By contrast, in so-called air-through systems, the trolleys are connected to the air chiller or a cooling station of the central cooling system via corresponding cooling air connections provided on the trolleys, so that the cooling air provided by the air chiller or the central cooling system can be passed directly through the trolleys. To avoid losses of cooling energy, trolleys provided for use in an air-through system must be provided with heat insulation and be sealed against leakages.
A cooling arrangement wherein the air-through principle is combined with an air-over system is described in EP 2 650 216 A1 and US 2013/292102 A2. In the cooling arrangement of EP 2 650 216 A1 and US 2013/292102 A2 a cooling fluid is circulated through a trolley received within a galley compartment via a cooling fluid inlet and a cooling fluid outlet of the trolley. In addition thereto, the galley compartment accommodating the trolley is provided with a cooling air inlet for supplying cooling air to the compartment and a cooling air outlet for discharging the cooling air from the compartment.